Homebrew all the way due to two game changers:
Emulation options and Cheats.
I can bet my whole reproductive system (and not just one testicle) that IF Nintendo ends up releasing Gamecube and/or Wii Virtual Console to the Switch, they will continue their stupid trend of releasing the emulators with no options for the end user.
What options?
Well, aspect ratio is the starting one, and they will have Gamecube locked at 4:3, even though a great variety of GC games support native 16:9.
Second, forced filters (darker screen) and changes to certain games will most likely come due to recent changes in videogame policies.
Really, the only thing they will be adding is customizable controls and that's about it, no screen ratio options, nor filters or at least border images if they keep their obnoxious 4:3 ratio.
No thanks, I'd much rather play my GC library through homebrew emulation, with proper 16:9 output and Widescreen cheat codes for games that have them. I don't care if I play them in upscaled 720p, both GC and Wii games look awesome in that resolution.
Same applies to all other consoles covered by the VC service.